Nothing sticks to textured sheet, not even PETG!  

RE: Nothing sticks to textured sheet, not even PETG!

I run my textured sheet for PETG at 85 Deg for the first layer and then 90 for the rest of the print and have no adhesion issues or warping.
I only give it a spray of IPA and wipe off with a paper towel between prints.

Once the print is finished, I lift the sheet off the heated bed and place it on a flat cold table top to help it cool down quickly, some prints pop off during cooling, but the majority I have to flex the sheet to get them off, and I use one of those plastic razor blades to remove the remaining PETG from skirt and purge lines and supports if any left behind.

My purge line is slightly raised as the original PRUSA settings caused damage to the textured surface and lifting of the texture.

And most important, I ONLY use PETG on the textured surface, if it so much as sees PLA, NOTHING sticks to it afterwards.

I have to do at least a couple of first layers of PETG over the part that had PLA on it to in effect peel off the PLA residue as well as a hot soapy wash and dry thoroughly before anything will stick to it again.

It used to be a PITA before PRUSA made the firmware be able to support separate sheets, but to be honest I hardly ever touch PLA nowadays, but am tempted by some of those Silk SUNLU filaments.

RE: Nothing sticks to textured sheet, not even PETG!

I was with you until you said "PRUSA made the firmware be able to support separate sheets".. So you are talking about the MK3 not the Mini?

I have zero issues with the Textured sheet on my MK3.. The only issue I have is with the Mini.. They don't even look the same.. The surface on the textures sheets look and feel totally different.

RE: Nothing sticks to textured sheet, not even PETG!

Sorry, I keep clicking on recent posts and replying, I wish this forum made it possible to filter results.

RE: Nothing sticks to textured sheet, not even PETG!

I recently got a new textured sheet for my Mk3 (white print) after having one from the first few runs (dark print, before it was available to order seperately).

I found the new one needed a lot of cleaning before anything stuck, I don't remember the old one being like this.  They are visibly different (old one marked WA-11 and new marked TF-25 in the top right, whatever that actually means)

RE: Nothing sticks to textured sheet, not even PETG!

WA = Works Alright?, I'll let you use your imagination for TF but Totally Finicky springs to mind 😉 

RE: Nothing sticks to textured sheet, not even PETG!

My textured sheet works great on the MINI for PETG using the stock profiles.  I have only used it for PETG, though.  A friend of mine recently had problems with his - the only difference we came up with is I keep mine covered (enclosure) and his is exposed to the air in his shop (he also does a lot of other stuff which might result in aerosols getting released).  He was able to get it back into service with Acetone (although this is not recommended regularly).

RE: Nothing sticks to textured sheet, not even PETG!

No one seems to have mentioned "extra-hold" hair stray. Works for me and easily removed with IPA when it builds up.

RE: Nothing sticks to textured sheet, not even PETG!

I designated one nail brush for cleaning textured sheet and use i when cleaning sheet with dish soap. It's funny listening to how PETG prints crack when it releases as sheet cools down.

RE: Nothing sticks to textured sheet, not even PETG!

Is the textured  sheet not recommended for PLA prints on the Mini?

I'm experiencing adhesion problems even after fiddling with z levels adjustments for hours

RE: Nothing sticks to textured sheet, not even PETG!

@omari

There doesn't seem to be a official recommendation for PLA on textured sheets, but from my very limited experience on the MK3S and that Prusa uses it mainly with PETG, I think the PLA bed-temperature is to low to get it sticky enough. My easy way out is printing PLA on the smooth sheet and PETG on the textured sheet on both printers. I didn't try much with brims or glue, that might help.

My MK3S textured sheet was original even too smooth for PETG to stick, but some mild sanding fixed that. For the Mini textured sheet that wasn't needed. So there is probably some variation in textured sheets.

RE: Nothing sticks to textured sheet, not even PETG!

@nibmaker

thank you very much! It helped! I spent many hours with IPA (99 %) only and PETG didn't want stick properly. Dish soap for new powder sheet is the solution and then IPA 🙂

RE: Nothing sticks to textured sheet, not even PETG!

I use dish soap and don't bother with IPA

regards Joan

RE: Nothing sticks to textured sheet, not even PETG!

I have 2000+ hours on my printer. Got the textured sheet and nothing (PLA, PETG, ABS) would stick to it. My guess is that there is a big difference between different batches. I ordered mine as soon as Prusa said they figured out large patch production during Mk3 release(2019 ish). 

Currently I can print PLA (60 C bed temp) and ABS (100 C bed temp) with no problem, but have no way of printing PETG (70 C bed temp). I will try 80-90 as recommended here. To get my bed working, I used similar method compare to @fjkraan and @tasmith2 . Differences being I used 300 or 400 grid sandpaper with light pressure to roughen up the surface. Then washed and cleaned like the two users above. Same idea.

With PETG(70C bed), the first layer prints perfectly, in fact, the first 10-20 layers are usually good. Once my z height gets above 5mm, the print would just pop off the bed, and give me spaghettis. My guess this is caused by shrinkage. With the smooth PEI, edge shrinkage may happen but the most can happen to the print is to have the very edge slightly detached. However with the powder coated PEI, edge shrinkage resulted in misalignment of the bumps on the bed surface, while the edges are getting pulled in, the misalignment could also push the print upward, thus potentially popping it off the bed.  

Note: I do use an enclosure all the time. This may contribute to my lower bed temp in ABS and/or lower bed temp in general.

At last, after reading all the posts here, I do have two experiments to try. #1 What if I sand down the powder coated bed so much to reduce the texture. Would that reduce the push-up effect from the shrinkage. (If shrinkage is the cause) #2 What would happen to adhesion (PLA, PETG, ABS) if I use rough sandpaper (60 grid or lower) on the smooth bed. 

RE: Nothing sticks to textured sheet, not even PETG!

I have a theory. Basically, there are two factors that reduces the top surface bed temperature of the textured bed comparing to the smooth one. #1 Textured aka uneven coating of PEI causes minor temperature differences across the surface. It can be as high as 8 degrees C when the bed is heating at full power. #2 Textured bed causes air to be trapped on the under side when magnetically held on. Air acts as insulator and reduces the temperature on the top surface.

I know my math is very rough, but here is my goal. Having reduced draft (enclosure or higher room temp) should help you with using the textured bed. Also, this might explain why PETG requires much higher temperature to print. (Normally people use 60C, but for textured bed, it is 80-90C) At last, do keep in mind, the 8 C temp drop is only with one side of the PEI. For heat to reach the printing plastic, it needs to go through 2 layers of it. So the 20C bed temp jump for PETG is not that unreasonable. This should be less of an issue for the smooth bed it is evenly coated (A sheet of PEI).

Math here.

K=(Q*d)/(A*deltaT)

Q: thermal transfer rate, aka wattage of the heating bed. Max draw is 6.25A at 24V =150W. I'm using the max value for the max possible temperature difference. I understand heating up to 70C does not require

d: Distance between two surfaces. I'm using the thickness of the smooth PEI layer 175um because I cannot find the coating thickness for the textured bed.

A: Area of the surface. I'm using the build surface here, being 0.21m *0.25m.

K: Thermal conductivity. For PEI, I found it to be 0.0644 W/m K, and is considered to be an insulator.

deltaT: Change of temperature between two surfaces. My assumption here is for textured bed, the thinnest part has no coating on it (same as steel sheet temp) while the thickest part has 175um of PEI on it. 

deltaT = (Q*d)/(K*A) = (150W*1.75*10^-4 m)/(0.0644W/m K *0.25m *0.21m) = 7.8 K or about 8 degress C

RE: Nothing sticks to textured sheet, not even PETG!

I have noticed huge differences in adhesion between two rolls of the same filament (color, type, manufacturer).  

RE: Nothing sticks to textured sheet, not even PETG!

Posted by: @cwbullet

I have noticed huge differences in adhesion between two rolls of the same filament (color, type, manufacturer).  

At least for me, I use high grade made in USA filament, which has shown to be completely consistent in properties roll to roll. My solution was steel wool over the textured, then wash with dish soap and HOT water every now and again. Works fine now. I did this to both my MK3s and my Mini textured sheets.

I now have a smooth PEI sheet on my Mini that is due for replacement. I'm going to remove the Prusa PEI sheet (which probably isn't going to be fun) and put on a Geckotek sheet, just to see if there is any noticeable difference.

RE: Nothing sticks to textured sheet, not even PETG!

Eesh, I feel like I got a good batch or something... I always run PETG with an 85C bed > 90C after the first layer (the stock settings in prusaslicer) and PETG sticks well enough that even the skirt can be a pain to get off sometimes. Plastic razors are a savior here to keep from touching the bed and having to clean it after ever print.

If it's popping off at upper layers, I would definitely up the bed temps, it's cooling and pulling it off the bed. Check your part cooling fan speed as well, 20~30% is fine. Too high might make it cool too fast, curl, and pull off the bed as well. When cleaning it with IPA, I have a small spray bottle and spray a good layer on the sheet and let it sit for a few seconds before cleaning it with a paper towel. Always work from the center out, or in a single direction so you don't just move it around and back again. I've been lazy and even use the same paper towel over and over and have had no issues. You can always try the smooth PEI sheet if you give it a quick wash with windex, friend of mine has the MK3S with only the smooth PEI and I told him about using windex and he's been loving it so far. 

A note about IPA, make sure to use 90% or higher, and try to aim for a 'decent' brand, none of the ones that are popping up to cash in on the current covid rush that might have some form of undesirable fillers that actually leave a residue. I've heard pharmacy store brands are decent though (such as Walgreens or CVS if you're in the US).  I've read it's mostly ones sold as "rubbing alcohol" instead of just saying Isopropyl alcohol tend to have some form of oil in them (maybe for the skin since marketed as an antiseptic for minor cuts?) An example taken from Wikipedia's article for rubbing alcohol is in Ireland and the UK "surgical spirit" which the British Pharmacopoeia defines as 95% methylated spirit, 2.5% castor oil, 2% diethyl phthalate, and 0.5% methyl salicylate. Check the "inactive ingredients" on the label of your IPA bottle. A thin layer of castor oil that doesn't evaporate I'm sure is just as bad as finger oils for adhesion, just a swipe of the fingers is enough to doom a print.

RE: Nothing sticks to textured sheet, not even PETG!

@skreelink

I would like to point out, "methylated spirit" most likely is ethanol with methanol in it. Also it is called denatured alcohol. This is not Isopropanol/Isopropyl Alcohol/IPA. Manufactures add methanol in it to prevent people from drinking/getting drunk on it. Meanwhile you cannot drink IPA so there tends to be less additives in IPA. Although both ethanol and IPA are good solvents, they will dissolve different residues. One example being glue leftover from stickers. ethanol usually does nothing but IPA can remove most of them.   

RE: Nothing sticks to textured sheet, not even PETG!

@hfan606

I don't think there is any Methanol in methalated spirits... 

Denatured alcohol, also called methylated spirits (in Australia, Canada, New Zealand, Ireland, South Africa, and the United Kingdom) or wood spirit or denatured rectified spirit,^[1] is ethanol that has additives to make it poisonous, bad-tasting, foul-smelling, or nauseating to discourage recreational consumption. It is sometimes dyed so that it can be identified visually. Pyridine, methanol,^[2] or both can be added to make denatured alcohol poisonous, and denatonium can be added to make it bitter.

Source  https://en.wikipedia.org/wiki/Denatured_alcohol#:~:text=Denatured%20alcohol%2C%20also%20called%20methylated,nauseating%20to%20discourage%20recreational%20consumption.

I just wash my build plates with dish soap and hot water...

RE: Nothing sticks to textured sheet, not even PETG!

@joantabb

Yep. That's why I only use IPA/Isopropanol/Rubbing Alcohol. 

The amount of methanol in methylated spirits is very low, but enough to stop people from drinking it. Unless you are into drinking methylated spirits, you should be fine.